Minecoprocessors by ToroCraft
This mods add a programmable block that functions like a microprocessor.
ExNihilo (for 1.7.2) by Erasmus_Crowley
A mod designed specifically for skyblock maps
Crying Obsidian by ErrorCraftLP
Crying Obsidian was intended to be a block that can change your spawn point, but it was never added to the game. This mod implements this block and adds an item version of it.